Cost minimization analysis of laparoscopic sacral colpopexy and total vaginal mesh




Objective


The objective of the study was a cost minimization analysis of the laparoscopic sacral colpopexy (LSC) and total vaginal mesh (TVM).


Study Design


Primary clinical costs were derived from our randomized control trial comparing LSC and TVM and were compared using prices from privately- and publicly-conducted procedures. Womens’ opportunity cost of time were added to these estimates to produce estimates of the primary economic costs of the procedures. Reoperation costs were added to estimate the economic cost per subject.


Results


LSC has lower mean primary clinical cost as compared with the TVM in both the public (mean difference, $1102.96; 95% confidence interval [CI], 468.52–1737.385) and private models (mean difference, $1176.68; 95% CI, 1116.85–1236.51), respectively. Mean total economic costs were significantly lower in the LSC group as compared with the TVM ($4013.07; 95% CI, 3107.77–4918.37). Labor costs were significantly greater in the LSC but were offset by lower consumable, inpatient, opportunity, and reoperation costs as compared with the TVM.


Conclusion


The LSC has lower economic cost than TVM.


Vaginal prolapse is an increasingly common problem affecting approximately 3-6% of community-dwelling American women, and the lifetime risk of surgery for pelvic organ prolapse varies between 6% and 19%. The need for pelvic organ prolapse surgery increases with age, and it has been conservatively estimated that the surgical workload related to pelvic organ prolapse will increase by 46% over the next 4 decades as our population ages.


Early this century there has been a paradigm shift in the surgical management of urinary stress incontinence from the colposuspension to the suburethral tapes. This change occurred after suburethral tapes were shown in randomized trials to be as effective as the colposuspension with reduced morbidity and decreased cost to the community.


The introduction of commercial kit meshes for vaginal prolapse occurred in 2004, and since that time there has been limited evaluation under the auspices of randomized controlled trials (RCTs), the outcomes of the RCT have been conflicting, and no cost evaluation has been performed from these studies. Traditionally gynecologists have based their decisions on surgical interventions based on the success rate, patient satisfaction, perioperative morbidity, and complications.


With rising health care costs, it is now imperative that clinicians include dollar cost of surgical interventions as a vital part of our decision making process. Despite considerable consumable costs, a sparsity of cost-effectiveness data exists on the vaginal prolapse mesh kits that are increasingly utilized in prolapse surgery. Our article presents a cost-minimization analysis (CMA) we conducted using formalized prospective data from our randomized controlled trial comparing the laparoscopic sacral colpopexy and the TVM for the treatment of vaginal vault prolapse.


This single-center, 2-surgeon (a urogynecologist and fellow) study demonstrated that in the perioperative period laparoscopic sacral colpopexy (LSC) was associated with longer operating time, longer admission time, and quicker return to activities of daily living as compared with TVM. At 2 years, on examination there was less recurrent prolapse and lower reoperation rate in the LSC group; however, no difference between the groups was seen in validated pelvic floor questionnaires. The aim of this study was to determine which of these 2 procedures has the lower total economic cost for the treatment for vaginal vault prolapse.


Materials and Methods


The CMA was conducted from the societal perspective. Within the Australian health system and within this study government, (public) payment or insurance (private) payment options are available and are detailed in our model ( Figure 1 ). We estimated the full costs of the procedures by capturing not only the financial flows associated with them, including operating room, labor costs, inpatient costs, consumable costs, and public and insurer expenditures, but also the productivity losses of the female participants in the study during their treatment and recovery. These cost categories were summed to compute the total economic costs for each procedure; however, we also present our data in disaggregated form to enable financial and other costs to be distinguished.




FIGURE 1


Outline of total economic cost calculation including primary clinical cost using public and private expenditure model

Maher. Cost analysis of laparoscopic sacral colpopexy and total vaginal mesh. Am J Obstet Gynecol 2012.


Australia has a public, universal health insurance scheme (Medicare) that involves zero-priced treatment for Australians who are treated as public patients. Thus, public admissions are funded directly by the Australian government including all costs of the admission.


The labor costs that were used in this study were calculated using data from operating room costs for all gynecological operations performed at the Royal Brisbane and Women’s Hospital from July to December 2008 and were tabulated using Transition II software, the hospital’s cost accounting system.


Total labor costs were divided by total operating time to achieve operating labor cost per minute and were as follows: anesthetist labor, $8.06; surgeon labor (including assistant), $7.04; and theater nursing labor, $32.19. Ward costs were estimated to be $785 per inpatient day and are listed in the Figure . Consumable costs included total vaginal mesh (Gynecare Prolift; Ethicon, Somerville, NJ) and suburethral obturator tape (TVT-O Gynecare; Ethicon) in vaginal group and trocars (Applied Medical, Rancho Sante Margarita, CA) self-styled Prolene mesh (15 × 15 cm; Ethicon) and hernia tacker to secure the mesh to the sacrum (ProTack 5 mm; Tyco Healthcare, Mansfield, MA) and are detailed in the Figure .


Under the no-gap private health insurance arrangements between insurers, hospitals, and practitioners, consumers are guaranteed zero copayment. Under this arrangement, the insurers reimburse the hospitals by paying a single fee that is based on the Commonwealth Medicare Benefits Scheme (CMBS) item descriptors, converted to diagnostic-related groups (DRG) using the International Statistical Classification of Disease and Health guidelines. The relevant DRG for all prolapse procedures performed vaginally and laparoscopically is N06Z and funds all operating room and ward cost excluding surgical and anesthetic medical staff.


Reimbursements of the surgeon and assistant are based on CMBS descriptors and in our model are based on the no-gap rate for the largest private health insurer, Medibank Private. The relevant descriptors in the laparoscopic group include sacral colpopexy (35597), retropubic prolapse/continence surgery (377044), posterior vaginal compartment surgery (35571), and cystoscopy (36812), and the vaginal group includes combined anterior and posterior compartment repair with mesh (35577), vault suspending procedure (35568), continence tape (35599), and cystoscopy (36812).


The cost of private anesthetic services are based on a unit fee including preoperative consultation (2 units), complexity of surgery (vaginal 5, laparoscopic 7 units), and 1 unit for each 15 minute block from entry to operating room until discharge to recovery. The anesthetic time in both vaginal and laparoscopic groups and public and private is calculated by adding 30 minutes to operating time defined as from knife to skin to completion of cystoscopy in our original paper. Medibank Private reimburses anesthetist at $32 per unit, in which units are defined per the Australian Medicare Benefits Scheme.


The opportunity cost of the time taken to recover from surgery is an important source of the societal costs of these procedures. In this study, the duration of recovery is measured as the number of days following surgery that a woman was able to return to her usual activities of daily living (ADL) as defined in our original paper as the time to return to driving, shopping, and meal preparation or return to work. Unfortunately, employment status, earnings, and other economic data were not recorded for the purposes of the RCT. Thus, we are required to make an assumption about the value of time during recovery. We assume that the opportunity cost per day of recovery is reasonably approximated by average adult ordinary total earnings, as reported by the Australian Bureau of Statistics 2010. Hence, the estimated opportunity cost per recovery day is $255.


Naturally because the mean age of women for both interventions was 63 years (SD 8.1 and 8.8 in the LSC and TVM groups, respectively), a substantial proportion of the sample is likely to be retired from the workforce. For these women, the opportunity costs of recovery may be overestimated, even if they engage in unpaid market and nonmarket (ie, household) production.


Conversely, older women who are in the workforce are likely to be longer than average in tenure and to have higher-than-average earnings. For these women, the opportunity cost of recovery time is likely to be underestimated. Thus, although we use average earnings as an approximation in this study, it would be useful for future studies of this population to collect detailed work-related data, including the value of paid and unpaid work. This information would enable a more accurate measure of the opportunity cost of women’s time, both at work and at leisure, to be constructed.


In the study by Maher et al, patients were treated under both the private model at the Wesley Hospital and the public model at the Royal Brisbane Hospital. To ensure the fairest representation of economic costs, 2 models are used and are represented by the Figure . The first model (model 1) assumes that all patients are treated as public patients and the second (model 2) assumes that all patients are treated as private patients. In each, costs are presented in disaggregate as well as aggregate form. Disaggregated clinical costs included the following cost categories for public patients: surgical costs, anesthetist costs, nursing costs, ward (inpatient stay) costs, and consumables. These categories are summed to compute primary clinical costs. The opportunity costs of recovery time are added to primary clinical costs to compute the primary economic cost.


To these costs, the costs of reoperations are added with disaggregations of the clinical and opportunity costs associated with them. The sum of primary economic costs and the economic costs of reoperations provides our estimate of total economic cost and our primary outcome analysis. This review should be read in conjunction with the original article describing the study methodology and the full outcomes in detail.


In model 2, the clinical costs are presented using no-gap reimbursement rates for the relevant Medicare items and DRG-related payment. This amounts to an assumption that the opportunity cost of clinical treatment is reflected in the no-gap rates that Australia’s largest private health insurer has negotiated with some hospitals and clinicians. The study protocol was approved by the institutional review board at the Royal Women’s (2004067) and Wesley hospitals (200445), and written informed consent was obtained from all participants on enrollment.




Economic Evaluation


Economic evaluation techniques provide systematic ways to compare the costs and consequences of clinical and other health sector interventions. Cost-utility analysis (CUA), a form of cost-effectiveness analysis, is by far the most commonly used, but alternatives include the cost-benefit analysis and the CMA. The CUA is particularly useful when 2 interventions create different health and longevity profiles (eg, drug A results in superior clinical results and also greater costs than drug B). If it is known that the health consequences of 2 interventions are clinically equivalent, CMA is an appropriate analytical approach.


Recall that the study by Maher et al used 2 validated and specific measures of outcomes 2 years following prolapse treatment, the Australian Pelvic Floor Questionnaire and the Kings College Pelvic Organ Prolapse quality of life, and found no statistically significant differences between the TVM and LSC groups. This result suggests that a CMA approach is an appropriate way to compare TVM and LSC. Nevertheless, the authors also found that there were short-term benefits for women who underwent the LSC, compared with those who underwent TVM treatment. These included shorter inpatient stays, quicker returns to ADL, and lower reoperation rates. These benefits are estimated in our CMA. Estimates of the full costs incurred in each arm of the trial provide a picture of the true economic costs of each treatment and enable their direct comparison.


Technically our estimates of marginal costs of the 2 procedures are based on average cost estimates for each group. Implicitly this entails the assumption that the mean costs experienced by each group represent the marginal costs that may be expected, on average, in practice. Effectively the population probability of using various disposable items, the chance of reoperations (etc) are assumed equal to the probabilities of use and reoperation observed in our samples.


Reoperation costs are estimated and based on expected parameters. If the probabilities of and reoperation costs differ between the LSC and TVM groups, it is appropriate to add the resulting, differential premiums to the index cost of each procedure.


Apart from the use of parametric statistics to compare the costs of the 2 procedures, and test for differences between them, a further sensitivity analysis is used by estimating the costs of performing these 2 procedures utilizing private insurance as per our model in the Figure . All costs are converted to American dollars on 2008 conversion.




Economic Evaluation


Economic evaluation techniques provide systematic ways to compare the costs and consequences of clinical and other health sector interventions. Cost-utility analysis (CUA), a form of cost-effectiveness analysis, is by far the most commonly used, but alternatives include the cost-benefit analysis and the CMA. The CUA is particularly useful when 2 interventions create different health and longevity profiles (eg, drug A results in superior clinical results and also greater costs than drug B). If it is known that the health consequences of 2 interventions are clinically equivalent, CMA is an appropriate analytical approach.


Recall that the study by Maher et al used 2 validated and specific measures of outcomes 2 years following prolapse treatment, the Australian Pelvic Floor Questionnaire and the Kings College Pelvic Organ Prolapse quality of life, and found no statistically significant differences between the TVM and LSC groups. This result suggests that a CMA approach is an appropriate way to compare TVM and LSC. Nevertheless, the authors also found that there were short-term benefits for women who underwent the LSC, compared with those who underwent TVM treatment. These included shorter inpatient stays, quicker returns to ADL, and lower reoperation rates. These benefits are estimated in our CMA. Estimates of the full costs incurred in each arm of the trial provide a picture of the true economic costs of each treatment and enable their direct comparison.


Technically our estimates of marginal costs of the 2 procedures are based on average cost estimates for each group. Implicitly this entails the assumption that the mean costs experienced by each group represent the marginal costs that may be expected, on average, in practice. Effectively the population probability of using various disposable items, the chance of reoperations (etc) are assumed equal to the probabilities of use and reoperation observed in our samples.


Reoperation costs are estimated and based on expected parameters. If the probabilities of and reoperation costs differ between the LSC and TVM groups, it is appropriate to add the resulting, differential premiums to the index cost of each procedure.


Apart from the use of parametric statistics to compare the costs of the 2 procedures, and test for differences between them, a further sensitivity analysis is used by estimating the costs of performing these 2 procedures utilizing private insurance as per our model in the Figure . All costs are converted to American dollars on 2008 conversion.




Statistical Analysis


Student t tests with unequal variances were performed to test the null hypotheses of no differences between the costs of LSC and TVM for all cost categories and subcategories. We report the means and SE for all cost estimates and report difference point estimates and their levels of statistical significance (ie, the 10%, 5%, and 1% levels) and 95% confidence intervals for all difference estimates.


In addition to testing for differences between costs for LSC and TVM subjects in both public and private hospital settings, we also tested the null hypothesis of no-cost difference between public and private procedures of the same type. Specifically we tested the null hypothesis of the no-cost difference between LSC (TVM) performed in a public hospital and LSC (TVM) performed in a private hospital. Statistical analyses were performed using STATA version 11 (2010; STATAcorp, College Station, TX).

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May 15, 2017 | Posted by in GYNECOLOGY | Comments Off on Cost minimization analysis of laparoscopic sacral colpopexy and total vaginal mesh

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